RPVCCA_SR_2011_03_01_09_Workshop_San_Ramon_Canyon_ProjectCITY OF
MEMORANDUM
RANCHO PALOS VERDES
TO:
FROM:
DATE:
SUBJECT:
HONORABLE MAYOR &CITY COUNCIL MEMBERS
RAY HOLLAND,DIRECTOR OF PUBLIC WORK.-...-..r-
MARCH 1,2011
WORKSHOP·SAN RAMON CANYON·PROJECT
STUDY REPORT
REVIEWED:CAROLYN LEHR,CITY MANAGER &-
Project Manager:Ron Dragoo,Senior Enginee~
RECOMMENDATIONS
1.Identify Alternative 1A as the Preferred Alternative;
2.Authorize Staff to solicit professional services for the preferred alternative
-design;
3.Authorize Staff to proceed with the sewer relocation design;
4.Direct Staff to provide regular land movement monitoring reports;and
5.Direct Staff to continue pursuit of funding opportunities.
BACKGROUND I ANALYSIS
The San Ramon Canyon drainage system poses ongoing threats to the City of RPV
and the community below 25th Street.Access along Palos Verdes Drive South is
frequently impacted during and following severe storm events.There is a possibility
that access could be cut-off entirely for an extended period should the 25th Street road
embankment fail.The lower switchback on Palos Verdes Drive East is being threatened
by progressive erosion within the canyon,largely as a result of the Tarapaca Landslide.
The landslide is causing the stream bed to move to the west which erodes the
embankment adjacent to the lower switchback.As the Tarapaca Landslide continues
to move,the Tarapaca neighborhood above the landslide is being threatened.The
community below 25
th Street is in the path of the drainage system,which could be
overwhelmed in a severe storm.The current system is not capable of managing large
amounts of debris that are generated within the canyon.
The City Council awarded a contract to Harris and Associates on March 16,2010 to
thoroughly investigate the conditions in the area and produce a Project Study Report for
the San Ramon Canyon Drainage System.The project studies include:the production
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of a detailed topographical survey,a geological investigation and report,a biological
review and other preliminary environmental studies,and production of a number of
alternative storm drainage designs for consideration.The information was used to
generate the Project Study Report,which evaluated the various designs and made a
recommendation of the most suitable alternative.
Concurrent with the generation of the Project Study Report,Harris and Associates have
produced a design for the Early Action PVDE Switchback Stabilization Project to
stabilize the lower PVDE switchback.The design is underway and will be discussed in
detail during the Workshop.
Staff has been working on the installation of a number of survey monitoring points,
which will be used to monitor any land-movement that may occur over several years in
the vicinity of the canyon to monitor the stability of the general area and to Document
erosion of the canyon near the switchbacks.
The generation of the Project Study Report has clearly identified a viable solution for
the drainage issues of the San Ramon Canyon and established an estimated cost
(Planning Level)for the project.The selection of a specific alternative will establish the
basis for a final design,utilizing the information obtained.
The City Council received and filed the Project Study Report and established March 1,
2011 as the date to conduct a workshop for the San Ramon Canyon Project Study
Report.The accepted report has become a tangible tool enabling the City to solicit
support for the project from agencies and groups,and will continue to be used in efforts
to obtain funding.
DISCUSSION
Staff's presentation to Council will include:a brief project background including the
cause and effect of land movement within the canyon,an overview of the current
canyon conditions,issues surrounding the canyon and design challenges,property
ownership within the canyon,a review of the project goals and summary of the report
including an analysis of the two most suitable design alternatives and
recommendations.The presentation will be followed by a detailed interactive
discussion on each of the alternatives and the recommendation to select a specific
solution.
Two alignments explored have been identified as the most suitable alternatives to
manage drainage within the canyon.Both alternatives start adjacent to the upper
PVDE switchback,and take into account the feasibility of the design,constructability,
geological considerations,environmental impacts and right-of-way requirements.Both
alternatives intercept the flows in the canyon at an inlet structure which will be located
in the vicinity of the upper switchback.Canyon flows will pipe the water to the ocean
and both recommend filling the canyon to a maximum depth of about 30-feet
downstream of the inlet structure,tapering off to zero at the City boundary
•The Canyon Alignment (Alternative 2A)pipes the water from the inlet structure
following the natural stream-bed,connecting to the existing City of Los Angeles
storm drain system which transports the runoff under 25th Street to the ocean.This
alignment has some major shortcomings and will require purchasing right of way,
and will require considerable coordination with outside agencies.
•The Tunnel Alignment (Alternative 1A)is the alignment Staff is recommending for9-2
your consideration.It is located completely within the City of RPV.The pipe will run
from the inlet structure through a tunnel to an existing easement in Shoreline Park
south of Palos Verdes Drive South.From there it runs parallel to the City boundary,
underground to its discharge point onto the beach.
In addition,a presentation will be made of the Early Action PVDE Switchback
Stabilization Project which is intended to be an interim project for stabilizing the lower
PVDE Switchback.
FISCAL IMPACT
Staff's recommendations will not have any immediate fiscal impacts.Assuming Staff's
recommendations are adopted,Staff anticipates returning to Council with a
recommendation to award a Professional Services Contract to design the preferred
alternative.The cost of those design service will be presented to Council at that time.
Likewise,Staff anticipates returning with a recommendation to award a construction
contract following the design and advertisement of the sewer relocation project.Staff
anticipates the design costs for the sewer relocation project will be in the neighborhood
of $5,000 to $10,000.Funding for the sewer relocation design can be funded through a
change order to the current Harris and Associates contract budget.
CONCLUSION
The report establishes a clear and feasible method to manage drainage within the San
Ramon Canyon and the problems associated with erosion generated in RPV within the
canyon.City Staff therefore recommends that the City Council:Identify Alternative 1A
as the Preferred Alternative;Authorize Staff to solicit professional services for the
preferred alternative design and proceed with the sewer relocation design;Direct Staff
to provide regular land movement monitoring reports;and
Direct Staff to continue pursuit of finding opportunities.
Attachment:January 18,2011 Staff Report (RAMON CANYON -PROJECT STUDY REPORT)
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CITY OF RANCHO PALOS VERDES
MEMORANDUM
Enginee~
JECT STUDY REPORTr,n1><,,-
HONORABLE MAYOR &CITY COUNCIL M
RAY HOLLAND,INTERIM DIRECTOR OF PUBLIC 1J'-
WORKS -
J:ahuary 18,2011
SAN RAMON CANYON·
LE.ClTV I\JIA
TO:
FROM:
DATE:
SUB·JECT:
REVIEWE;D:
Project Mana.ger:
RECOMMEN't)ATIONS
1.Receive and File the Project Study .Report for San Ramqn
2.Set March 1,2011,du regu $ched:uleq City
date to oonduct a Public kshop he San Ramon Can
Report.
BACKGROUND I ANALYSIS
",
Conditions within the San rious threat to the
accessibility of tlie Ci st during flooding on 25th Street.
Land movement and erosion within the can ating a scenarioftlr potential loss
of the access corridor along Palos Verdes Drive To address the.sethreats,City
awarded a contract to H;:l(ris ;:lnd Associates on March 16,2010 to produce a
Proj Report for the Ramon Canyon Drainage System.The project studies
included tasKs like:the prod ion of a Hed topographical survey,geological
investigation and report,a biological review,an environmental study,and production of
a number of storm drainage designs.The information was used to generate the Project
Study Report,which evaluated the various designs and made a recommendation of the
most suitable alternative.
The report.proposes various alternatives and will be used as the basis for a final design
and can be used as a tool to solicit support and funding for the project.
Two of the alignments explored start adjacent to the upper PVDE switchback,and take
into account the feasibility of the design,constructability,geological considerations,
environmental impacts and right-of-way requirements,
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•'One alignment follows th
drainage system (2A)in ,of
19 sstern has some major sho
and uire consjQ~r:able co.orc;lina .10 "
•Th,e recommends ment (1A)is totally within the
run t extends frQmtbe upper switc
efl Pa*$outh ,'s Verde$Drive
p 'I boundary,within R,undergrb,und to its
t
The Project Study Report 'is:ayail~bl.ei for review at City Helland js~on file wJth the
Clerk's Office.st<il,ff proposes<tc presentthe.ProjectSt eater detail to
ou 'ta Workshop.,Staff is·suggestil1g sehedul g the p for Maroh 1,
to f te discUssion cnthe merits o.fthe :destgns.'
Pursuant to Oity Council dire.Qtion-tM~r,Ch 16,20 i Harris &Assoc.iates
c:t to proVic;le shQrt:tetm.$t?bility or the P "
a'cons to :mQn ",stability of the area
erosion in the ty Of t
s •ovel ready project and report on
a W-orksnop in March.,.
FISCAL IMPACT
The Receiving and Filing of this report notcohstlfute·.a Fiscal Impact,h
in'g level estimates for the two a mafives discussed range from $18.
iUkm .
.rt establishes a clear and feasible .ethod.to manag
an'd the'problems as.so with erosion
y Staff therefore re~ommends that:
t StlJ:dy eport;-8 t March 1,2011,regut
Counoil Meeting,as the d to condUct a Public Workshop'fa
Project StUdy Repbrt.
Attachment:Project Study Report (see separate San Ramon Project Study Report binder)
Sketch of Alternatives
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